Junko S. Hiraga
A5050685201- Astrophysical Phenomena and Observations
- Particle Detector Development and Performance
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- CCD and CMOS Imaging Sensors
- Advanced X-ray Imaging Techniques
- Advanced X-ray and CT Imaging
- Pulsars and Gravitational Waves Research
- Medical Imaging Techniques and Applications
- Nuclear Physics and Applications
- Solar and Space Plasma Dynamics
- Radiation Detection and Scintillator Technologies
- Astronomy and Astrophysical Research
- Calibration and Measurement Techniques
- Advanced Optical Sensing Technologies
- Adaptive optics and wavefront sensing
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Infrared Target Detection Methodologies
- X-ray Spectroscopy and Fluorescence Analysis
- Ionosphere and magnetosphere dynamics
- Dark Matter and Cosmic Phenomena
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Integrated Circuits and Semiconductor Failure Analysis
Kwansei Gakuin University
2016-2025
National Astronomical Observatory of Japan
2025
University of Miyazaki
2022-2024
The University of Tokyo
2010-2024
Goddard Space Flight Center
2010-2024
Tokyo Metropolitan University
2016-2024
Aoyama Gakuin University
2024
Kobe Gakuin University
2023
Kanto Gakuin University
2018-2022
Osaka University
1989-2020
The XIS is an X-ray Imaging Spectrometer system, consisting of state-of-the-art charge-coupled devices (CCDs) optimized for detection, camera bodies, and control electronics. Four sets sensors are placed at the focal planes grazing-incidence, nested thin-foil mirrors (XRT: X-Ray Telescope) onboard Suzaku satellite. Three have front-illuminated CCDs, while other has a back-illuminated CCD. Coupled with XRT, energy range 0.2–12 keV resolution 130 eV 5.9 keV, field view $18^\prime \times...
High-sensitivity wide-band X-ray spectroscopy is the key feature of Suzaku observatory, launched on 2005 July 10. This paper summarizes spacecraft, in-orbit performance, operations, and data processing that are related to observations. The scientific instruments, high-throughput telescopes, CCD cameras, non-imaging hard detector also described.
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by Institute Space and Astronautical Science (ISAS). will investigate physics high-energy universe performing high-resolution, high-throughput spectroscopy with moderate angular resolution. covers very wide energy range from 0.3 keV to 600 keV. allows combination band (5-80 keV) provided multilayer coating, focusing hard mirrors imaging detectors, high energy-resolution soft (0.3-12...
We present results obtained from a series of observations the supernova remnant RX J1713.7-3946 by Suzaku satellite. The cover about two-thirds surface. successfully detected hard X-rays up to ~ 40 keV each pointing. X-ray spectra are described power-law functions with photon indices 3.0, which larger than those in energy region below 10 keV. Connection spatially-integrated XIS and HXD clearly reveals spectral cutoff 0.4--40 spectrum. This is interpreted correspond maximum acceleration...
The ASTRO-H mission was designed and developed through an international collaboration of JAXA, NASA, ESA, the CSA. It successfully launched on February 17, 2016, then named Hitomi. During in-orbit verification phase, on-board observational instruments functioned as expected. intricate coolant refrigeration systems for soft X-ray spectrometer (SXS, a quantum micro-calorimeter) imager (SXI, CCD) also However, March 26, operations were prematurely terminated by series abnormal events mishaps...
Abstract High-resolution X-ray spectroscopy with Hitomi was expected to resolve the origin of faint unidentified emission line reported in several low-resolution studies various massive systems, such as galaxies and clusters, including Perseus cluster. We have analyzed first-light observation The for based on XMM-Newton signal from large cluster sample under dark matter decay scenario is too be detectable data. However, previously 3.5 keV flux anomalously high compared sample-based...
Extending the earlier measurements reported in Hitomi collaboration (2016, Nature, 535, 117), we examine atmospheric gas motions within central 100~kpc of Perseus cluster using observations obtained with satellite. After correcting for point spread function telescope and optically thin emission lines, find that line-of-sight velocity dispersion hot is remarkably low mostly uniform. The reaches maxima approximately 200~km~s$^{-1}$ toward active galactic nucleus (AGN) AGN inflated...
The Hitomi SXS spectrum of the Perseus cluster, with $\sim$5 eV resolution in 2-9 keV band, offers an unprecedented benchmark atomic modeling and database for hot collisional plasmas. It reveals both successes challenges current codes. latest versions AtomDB/APEC (3.0.8), SPEX (3.03.00), CHIANTI (8.0) all provide reasonable fits to broad-band spectrum, are close agreement on best-fit temperature, emission measure, abundances a few elements such as Ni. For Fe abundance, APEC measurements...
Supernova remnants (SNRs) retain crucial information about both their parent explosion and circumstellar material left behind by progenitor. However, the complexity of interaction between supernova ejecta ambient medium often blurs this information, it is not uncommon for basic progenitor type (Ia or core-collapse) well-studied to remain uncertain. Here we present a powerful new observational diagnostic discriminate types constrain density SNRs using solely Fe K-shell X-ray emission. We...
The X-Ray Imaging and Spectroscopy Mission (XRISM) is the successor to 2016 Hitomi mission that ended prematurely. Like Hitomi, primary science goals are examine astrophysical problems with precise highresolution X-ray spectroscopy. XRISM promises discover new horizons in astronomy. carries a 6 x pixelized micro-calorimeter on focal plane of an mirror assembly co-aligned CCD camera covers same energy band over large field view. utilizes heritage, but all designs were reviewed. attitude orbit...
Abstract Supernova remnants ($=$ SNR) are suggested to be sites of cosmic-ray acceleration. In particular, it has been an issue keen interest whether cosmic ray protons being accelerated in a SNR which emits TeV $\gamma$-rays. A crucial observational test for this is find dense molecular gas towards the SNR, because such can best verify existence via pion decay Here, we show that new high-resolution mm-wave observations interstellar CO molecule have revealed at 1 kpc distance interacting...
We present the Suzaku spectroscopic study of Galactic middle-aged supernova remnant (SNR) IC 443. The X-ray spectrum in 1.75–6.0 keV band is described by an optically thin thermal plasma with electron temperature ∼0.6 and several additional Lyman lines. robustly detect, for first time, strong radiative recombination continua (RRC) H-like Si S around at 2.7 3.5 keV. ionization temperatures determined from intensity ratios RRC to He-like Kα lines are ∼1.0 ∼1.2 keV, respectively. thus find firm...
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by Institute Space and Astronautical Science (ISAS). will investigate physics high-energy universe via suite four instruments, covering very wide energy range, from 0.3 keV to 600 keV. These instruments include high-resolution, high-throughput spectrometer sensitive over 0.3-2 with high spectral resolution Delta E < 7 eV, enabled micro-calorimeter array located focal plane thin-foil...
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions developed by Institute Space and Astronautical Science (ISAS), with planned launch 2015. equipped suite sensitive instruments highest energy resolution ever achieved at E > 3 keV wide range spanning four decades from soft X-rays to gamma-rays. simultaneous broad band pass, coupled high spectral Delta < 7 eV micro-calorimeter, will enable variety important science themes be pursued. expected...
The Hitomi (ASTRO-H) mission is the sixth Japanese X-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. aimed to provide highest energy resolution ever achieved at E > 2 keV, using microcalorimeter instrument, cover wide range spanning four decades in from soft X-rays gamma-rays. After successful launch on 2016 February 17, spacecraft lost its function March 26, but commissioning phase for about month provided valuable...
The purpose of this study was to investigate the effect directions extraoral maxillary protraction forces on biomechanical changes in craniofacial complex, using three-dimensional finite element method (FEM). A FEM model developed basis a young, human dry skull. consisted 2918 nodes and 1776 solid elements. An anteriorly directed 1.0 Kg force applied buccal surface first molar varying from -90 90 degrees occlusal plane. displacement pattern entire complex evaluated. Further, stress...
Thanks to its high spectral resolution (~5 eV at 6 keV), the Soft X-ray Spectrometer (SXS) on board Hitomi enables us measure detailed structure of spatially resolved emission lines from highly ionized ions in galaxy clusters for first time. In this series papers, using SXS we have measured velocities gas motions, metallicities and multi-temperature core Perseus cluster. Here, show that when inferring physical properties line emissivities systems like Perseus, resonant scattering (RS) effect...
We report the first detection of thermal X-ray line emission from supernova remnant (SNR) RX J1713.7-3946, prototype small class synchrotron-dominated SNRs. A softness-ratio map generated using XMM-Newton data shows that faint interior regions are softer than bright shell regions. Using Suzaku and deep observations, we have extracted spectra softest area, finding clear features at 1 ∼1.35 keV. These lines can be best explained as Ne Lyα Mg Heα a component. Since abundance ratios metals to Fe...
A galactic supernova remnant (SNR) Vela Jr. (RX J0852.0$-$4622, G266.6$-$1.2) shows sharp filamentary structure on the north-western edge of in hard X-ray band. The filaments are so smooth and located most outer side remnant. We measured averaged scale width ($w_u$ $w_d$) with excellent spatial resolution {\it Chandra}, which order size point spread function Chandra} upstream 49.5 (36.0--88.8) arcsec downstream side, respectively. spectra very have no line-like structure, were well...
The present paper investigates the temperature structure of X-ray emitting plasma in core Perseus cluster using 1.8--20.0 keV data obtained with Soft Spectrometer (SXS) onboard Hitomi Observatory. A series four observations were carried out, a total effective exposure time 338 ks and covering central region $\sim7'$ diameter. SXS was operated an energy resolution $\sim$5 eV (full width at half maximum) 5.9 keV. Not only fine structures K-shell lines He-like ions but also transitions from...
The Soft X-ray Imager (SXI) is the charge-coupled device (CCD) camera for soft imaging telescope Xtend installed on Imaging and Spectroscopy Mission (XRISM), which was adopted as a recovery mission Hitomi satellite successfully launched 2023 September 7 (JST). In order to maximize science output of XRISM, we set requirements find that CCD employed in Hitomi/SXI or similar, i.e., $2 \times 2$ array back-illuminated CCDs with $200~\mu$m-thick depletion layer, would be practically best among...